1. Field of the Invention
The invention relates to an oolong tea beverage (a drink) filled in containers such as cans, paper drink boxes, and plastic bottles and sold and a process of producing the same. Particularly, the invention relates to an oolong tea beverage produced by especially strongly extracting a particular scent of oolong tea with high quality and a process of producing the same.
2. Related Art Statement
Tea can broadly be classified into three types; green tea (unfermented tea), black tea (fermented tea), and oolong tea (semi-fermented tea). They are all derived from tea tree (scientific name: Camellia sinensis) belonging to Camellia genus, Camellia family and depending on the processing method for tea leaves, mainly the difference of fermentation extents, teas with totally different color, flavor, and taste are produced.
Oolong tea is a semi-fermented tea produced by stopping the oxidative fermentation of tea leaves in the middle of the process. The raw material tea leaves of the oolong beverage (a drink) are generally produced by sun-drying picked-up tea leaves or drying them in the shade, oxidizing and fermenting the dried leaves in the insides of bamboo baskets, stopping the fermentation by roasting the leaves when the oxidation fermentation are promoted to 30% to 70% extent, and rubbing and hot air-drying the obtained leaves.
One of particular characteristics of oolong tea is deep and rich flower smell (flower scent). It is said that the flow scent is derived from terpene type alcohols such as linalool, geraniol, and nerolidol, and aroma components such as jasmine lactone, methyl jasmonate, cis-jasmone, and indole.
Conventionally proposed processes of producing oolong tea will be exemplified as follows.
Japanese Patent Application Laid-Open No. 5-236876 discloses a process of producing concentrated oolong tea by putting oolong tea leaves in a hot water containing at least one of ascorbic acid, cyclodextrin and starch, boiling the water for extracting the oolong tea components, filtering the extract by a filter such as a filtration cloth, a filtration paper, or a cartridge for removing sediment, and separating and recovering a concentrated liquid from the filtered extract by reverse osmosis.
Japanese Patent Application Laid-Open No. 11-289983 discloses a process of producing canned oolong tea, comprising: a first sterilization step of sterilizing oolong tea extract by instantaneous sterilization at ultrahigh temperature; and a second sterilization step of keeping the extract at 90° C. or higher for about 20 seconds after pouring the extract in a can and turning the can upside down, and then keeping the resulting extract at 85° C. or higher for 4 to 5 minutes.
Japanese Patent Application Laid-Open No. 11-113491 discloses a process of producing a tea type beverage by removing a cold water-extracted solution obtained by extracting teas with cold water at 20° C. or lower and re-extracting the tea residues with hot water at 30 to 95° C.